Return bend closure



May 29, 1934. I H. J. KERR ET AL RETURN BEND CLOSURE Filed Jan. 25, 1929 F5 z Patented May 29, 1934 RETURN BEND CLOSURE Howard J. Kerr, Westfield, N. 1., assignor to The Babcock & Wilcox Company, Bayonne, N. J., a corporation of New Jersey Application January 25,1929, Serial No. 335,040

6 Claims.

This invention relates to an improved form of return bend such as is used in superheaters and the like, and the novel features thereof will be best understood from the following description and the annexed drawing. In the cm:

in which there is shown a selected m ent of the invention,

Fig. 1 is a fragmentary elevation of a portion of a boiler having the invention applied to a sum perheater therein,

Fig. 2 is a section on an enlarged scale on the line 2-2 of Fig. 3, and showing the novel features of the return bend.

Fig. 3 is a view of the bend shown in Fig. 2,

and taken from the left of that figure.

For the purposes of illustration, I have shown the invention as applied to a superheater indicated generally at 1 and which is disposed between banks 2 and 3 of a boiler, the hot gases 0 flowing through a. pass in which the superheater' is disposed, one side of this pass being formed by baflling 4. The superheater is shown as composed of a plurality of substantially parallel tubes having loops or bends 5 at their outer ends and provided at their inner ends with the return bends 6 forming the subject matter of this appllcation. These bends may be connected to the respective tubes of the superheater as by welding, and each bend is preferably provided with a plurality of branches 7, each one of which may thus be welded or otherwise secured to a tube. The two branches are provided with a connecting passageway 8 and communicating with this passage is a tubular neck 9. The walls 5 of this neck extend through the battle 4, and means is preferably provided for opening and closing this neck so that a tool may be inserted through the neck into either one of the branches '1. In the neck is a stopper seat 10 here shown as frusto-conical in form, and on this seat is a stopper 11 which is shown as follow in form and with an outer frusto-conical surface 12 adapted to contact with the stopper seat 10. The inner. surface 13 of the stopper is also preferably frusto-conical in form, but forms a greater angle with the axis of the passage through the neck 9. The result is that the wall 14 between the inner and outer surfaces is in the form of a wedge.

Disposed within the hollow stopper is a member'15, here shown as a solid button havin a frusto-conical surface 16 adapted to contact with the surface 13 of the stopper, and also having a rounded head adapted to contact with a flat surface 17 on a plug 18 which is threaded into the neck 9. This plug is preferably provided with holes 19 by means of which it may be ascertained whether or not steam is through the stopper.

After the parts are assembled, any movement of 13 the stopper 11 towards the left of Fig. 2, will result in wedging it more tightly in place. Preferably this stopper 11 is made of material which is soft in comparison to that of the bend in. which it is located. For exple, it may be made of :5 copper, which is soft as compared to the metal of the bend. The plug may be orated to adjust the stopper as desired.

I claim:-

1. A. closure device for a return bend having at 1 least two branches connected by a passage in a tubular neck which is formed to provide a closure seat, a closure member having a wedge shaped portion adapted to contact with said seat to form a pressure tight closure for the return 7 bend, a second closure member in the form of a frusto-conical button or plug with a sloping face in contact with said wedge portion, and means to force said second closure member along the neck and non-rotatably into the first closure mem- 8 mer to cause it to have pressure tight engagement with said seat.

2. A closure device for a return bend having at least two branches connected by a passage within a tubular neck which is formed to provide a frusto-conical closure seat, a hollow closure member having inner and outer frusto-conical and non-parallel surfaces and engaging said seat at its outer surface, a second closure member adapted to contact with the inner surface of the first, and means rotatable with respect to the second member for forcing the latter into the first member to expand it against said seat.

3. A closure for a return bend having two branches connected by a passage within a tubular neck which is formed with a frusto-conical closure seat, a hollow closure member having inner and outer frusto-conical surfaces with the inner surface forming a greater angle with the axis of the passage than the outer surface which is 1 adapted to contact with said seat, a second closure member having a frusto-conical face adapted to contact with the inner surface of the first member, and means having a point contact with the second member to non-rotatably force it into such engagement with the inner surface of the first member that a pressure tight closure for the return bend is formed.

4. In fluid heat exchange apparatus; a closure construction exposed on one side to hot furnace 11o gases and subjected on the other side to high fluid pressures; said construction including a part formed to provide a port presenting a frustoconical closure seat opening toward the gases, a flexible hollow metallic stopper having an outer annular face adapted to contact with the seat in fluid tight relationship and presenting an inner annular face, the portion of said stopper between said inner and outer annular faces constituting a wedge-shaped annular flange, a plug tightly fitting within the stopper so that it does not completely fill the space therein, and means for forcing the plug along the seat to expand the stopper thereagainst in fluid tight relation during which the tendency of fluid pressure on the stopper is to force its flange up on the plug to expand the stopper more tightly against the seat, the plug moving without rotation to exert said pressure on the stopper.

5. A pressure seal construction comprising, in combination, a container wall formed with a port presenting a flaring closure seat, a plug having a frusto-conical part, means for forcing the plug toward the base of the closure seat, and a stopper having a wedge-shaped flange adapted to be forced into fluid tight relationship with the seat by movement of the plug, and adapted to be expanded against the seat by the fluid pressure when the plug is held stationary, said wedge shaped flange having its thickest portion adjacent the fluid contacting face of the stopper.

6. In combination with fluid conducting tubes of fluid heat exchange apparatus, a branched fltting connecting a plurality of tubes, an apertured stem projecting from the side of the fitting opposite the branches, said stem having a thickened wall portion formed to provide a closure seat adjacent the branches, a closure structure including a hollow member having a pressure tight engagement with the seat, the closure seat and closure structure being so positioned that the-face of the latter forms substantially a continuation of the inside walls of the fitting, and a plug acting as a pressure applying device threaded into the stem to directly engage the closure structure and force it into pressure tight engagement with its seat.

HOWARD J. KERR. 

